Circuit à réaction

Résumé

Un circuit à réaction permet d'amplifier un signal électronique à répétition par le même tube électronique ou autre élément électrique tel un transistor à effet de champ. Inventé par Edwin Howard Armstrong en 1912 , un tel circuit consiste en un tube électronique amplifiant dont la sortie est connectée à son entrée en boucle à rétroaction, ce qui engendre une réaction positive. Ce type de circuit était très utilisé dans les récepteurs radio entre 1920 et la Seconde Guerre mondiale. Ils sont toujours en usage dans les produits électroniques simples, tels les ouvre-porte de garage. Fonctionnement Dans un circuit à réaction, la sortie d'un tube électronique amplifiant est connectée à son entrée via une boucle à rétroaction ainsi qu'un circuit LC qui sert de filtre. Le circuit LC ne permet de la réaction positive qu'à sa fréquence de résonance. Le wikt:circuit accordé est également relié à l'antenne et permet de sélectionner la fréquence radio à recevoir : il est réglab

Source officielle

https://fr.wikipedia.org/wiki/Circuit_%C3%A0_r%C3%A9action

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Concepts associés (26)

Un récepteur radio, aussi appelé simplement radio ou poste de radio, est un appareil électronique destiné à capter, sélectionner et décoder les ondes radioélectriques émises par les émetteurs radio.

thumb|Récepteur superhétérodyne à cinq tubes de fabrication japonaise (1955). En électronique, un récepteur hétérodyne est un récepteur conçu sur le principe du mélange de fréquences, ou hétérodynage

vignette|Un oscillateur intégré à quartz. Un oscillateur électronique est un circuit dont la fonction est de produire un signal électrique périodique, de forme sinusoïdale, carrée, en dents de scie, o

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Analysis, modeling and design of a CMOS Super-Regenerative Receiver for implanted medical devices under square and sinusoidal quench signals

Catherine Dehollain, Naci Pekçokgüler

Medical implant devices have found widespread application in recent years. The Super-Regenerative Receiver has been one preferred architecture due to its power advantage over other architectures. We present a detailed analysis of the circuits and their equivalent models to be used in system level design of a Super-Regenerative Receiver in this paper. The design procedure is also demonstrated with a receiver design example. Designs were carried out in UMC 180 nm process with a center frequency of 416 MHz for MedRadio band. Errors between the simulation results of the proposed model and actual circuits are less than 1.6% for LNA characteristics and 7% for receiver output amplitude. 10 Mbps data rate was achieved with 432 pJ/bit energy consumption over 1.8 V power supply. The study is concluded with the simulation results of the circuits and the equivalent models.

ELSEVIER SCIENCE BV2019

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Communication systems have played a key role in changing our lives as such systems help to access remote data and to transfer it to the end user when requested. Intelligent nodes, which can process and transmit information placed in a given environment can provide localized data that might not be available through a public network such as the internet. As an example, nodes can provide dynamic data such as room temperature, chemical composition of air, or light intensity level. With the progress made in the semiconductor industry, such nodes have become compact, thereby making it easier to setup a cluster in a confined place. Often these nodes are to be placed in a remote location and hence the use of a cable to power up these devices might not be possible. Also, the use of cables makes the system bulky and heavy. For this reason battery-powered wireless sensor nodes are desirable. Such battery operated devices need to be energy efficient to avoid replacing the batteries often. Energy efficiency can be achieved by optimizing several parameters from the top (system level architecture) to the bottom (transistor level design). The thesis describes a receiver system design for Impulse-radio Ultra-Wideband (IR-UWB) signalling standard proposed in IEEE 802.11.4a for short range, low data rate communication system. The advantages of the IR-UWB signalling scheme over other existing standards and a comparison between various receiver architectures for IR-UWB standard using energy consumption as a metric is described. The main power consuming block in an IR-UWB receiver is identified to be the front-end amplifier structure as it needs to provide sufficient gain for proper operation of the subsequent stages. To reduce the power consumption of this amplifier, the super-regenerative architecture for IR-UWB system is proposed. It is shown in this work that since the super-regenerative receiver uses an amplifier with positive feedback, it can achieve high gain with a relatively low current, hence it can significantly reduce the power consumption. The super-regenerative receiver for the IR-UWB system is implemented in a 0.18 µm CMOS technology operating at 1.5 V, and the receiver energy consumption is 0.24 nJ/bit at a data rate of 10 Mbps. The receiver achieves a measured sensitivity of -66 and -61 dBm at 3.494 and 3.993 GHz, respectively, with a BER of 10-3. Finally, an automatic tuning circuitry based on a digital phase-locked loop architecture (DPLL) for super-regenerative receiver is proposed. The objective is to tune the receiver to either one of the sub-bands (3.494 or 3.993 GHz) as proposed in the IEEE 802.15.4a standard. Including the tuning circuitry helps to improve the receiver sensitivity, and also demonstrates the possibility for multi-band reception using such an architecture. The proposed DPLL is implemented in a 0.18 µm CMOS technology consuming 9.3 mW.

EPFL2010

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An automatic pulse alignment method for slope controlled super-regenerative receiver systems

Michel Declercq, Catherine Dehollain

Recently there is an increase in interest for using super-regenerative receivers for pulse based communication systems. To receive a pulse using the super-regenerative architecture the pulse needs to be aligned with the zero crossing of the damping co-efficient (which depends on the quench signal) for achieving maximum sensitivity. In general, the pulse to be received is not aligned with the zero crossing of the damping co-efficient. In this paper a novel technique for an automatic alignment of the incoming pulse with the zero crossing in a slope controlled super-regenerative system is proposed. The proof of concept is shown using MATLAB simulations. Also a complete digital delay line architecture for delaying the quench signal which is a critical block in pulse alignment is described.

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EPFL2010